best/worst Cellphone audio informal poll

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Greatings

Here's an unusual request. I'm currently working in the acoustics
engineering group for a large cell phone company. We have lots of
industry formal test requirements that most all phones pass. This
seems to have little direct correlation to percieved quality either
recieved or Sent audio. I'm interested in the opinion of trained ears.
On GSM mostly but CDMAs OK. Please If you find the time just find a
stationary known good RF spot at a non busy hour time and reply with
your type/model and opinions. I'm interested in audio not RF
performance so minimum BER/FER is needed.

Thanks
Kevin Tracy
 
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On 5 May 2005 07:29:15 -0700, "KGT" <kgtracy@gmail.com> wrote:
>Here's an unusual request. I'm currently working in the acoustics
>engineering group for a large cell phone company. We have lots of
>industry formal test requirements that most all phones pass. This
>seems to have little direct correlation to percieved quality either
>recieved or Sent audio. I'm interested in the opinion of trained ears.
>On GSM mostly but CDMAs OK.

I'm not sure this has anything to do with your request, but I'm
curious about it. My carrier (US Cellular, Northern California) just
switched us from TDMA to CDMA 1xRtt. On TDMA the RF performance was
dismal, but I couldn't tell from the audio whether my Ericcson T18d
was using TDMA or analog - both sounded decent on voice and music.

On the new CDMA system, with a Moto V710m, RF performance is vastly
improved. Voice is much more intelligible, which I think is due to
better AF, transducer, and ergonomics rather than any effect of the
coding scheme. But music is unbearable - sounds raspy, and like it is
bubbling up from underwater. I find myself hanging up when I'm put on
hold so I don't have to listen to it.

The bult-in MP3 player sounds amazingly good, so the horrible music
performance clearly is the coding scheme. I can run a measured 62K of
computer data through the 1xRtt link, so how can it be that they can't
do a better job of reproducing music on hold with that much bandwidth
available? I'm probably on the most lightly loaded cell in the system,
in a remote area no other company even bothers to serve, so it isn't a
matter of oversubscribing the hardware.

Loren
 
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Loren

The CODECs in CDMA (and others technologies) are optimized for speech
at the cost of non speech. They don't like tones, music etc. This is
the price for squeezing that much bandwidth and features out of an 8k
(EVRC) coder. or for that matter a 13k.

Kevin Tracy
 
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In article <1115303355.739930.68680@f14g2000cwb.googlegroups.com> kgtracy@gmail.com writes:

> Here's an unusual request. I'm currently working in the acoustics
> engineering group for a large cell phone company. We have lots of
> industry formal test requirements that most all phones pass.

What a pity!


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Ok Mike

But given my options (daughter in college NJ mortgage/taxes/roots) and
20 years invested in Bell labs I could have landed from my 1 year in
downsized telecom hell in a lot worse places Also This was a sincere
attempt to get skilled opinions from this group.

PS I'm still a serious weekend warrior musician/engineer as I have been
for 30 years.

KT
 
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Randy

To put this back on track.. what model GSM phone do you use as a
benchmark of Good downlink SPEECH quality? Do you have one that you
rate poor?

Loren
No currently deployed CELP coder (I believe AMR Is CELP?) can reproduce
music well. Its meant for speech! No matter what the RF FER is.

All
I'm still interested in RAP opinions on phones that have surprized you
with very good or very bad SPEECH.

Thanks
Kevin Tracy
 
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Randy

To put this back on track.. what model GSM phone do you use as a
benchmark of Good downlink SPEECH quality? Do you have one that you
rate poor?

Loren
No currently deployed CELP coder (I believe AMR Is CELP?) can reproduce
music well. Its meant for speech! No matter what the RF FER is.

All
I'm still interested in RAP opinions on phones that have surprized you
with very good or very bad SPEECH.

Thanks
Kevin Tracy
 
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Loren Amelang <loren@pacific.net> writes:
> [...]
> I'm probably on the most lightly loaded cell in the system, in a
> remote area no other company even bothers to serve, so it isn't a
> matter of oversubscribing the hardware.

Rappaport [1] states that QCELP13 is a higher-datarate speech codec
for IS-95 systems. You can also read some interesting history about
the CDMA codec evolution at

http://www.commsdesign.com/design_corner/showArticle.jhtml?articleID=16500249

Regarding your situation, perhaps you're at the distance limits of the
cell, or the cell is operating at reduced power, thus they may be
dropping to a lower speech codec rate in order to perform more channel
coding.

Have you tried a GSM phone? Most of the GSM networks now support AMR
(Adaptive Multi-Rate), an improved variable-rate codec system.

--Randy

[1] @BOOK{rappaport,
title = "{Wireless Communications: Principles and Practice}",
author = "{Theodore~S.~Rappaport}",
publisher = "Prentice Hall PTR",
edition = "second",
year = "2002"}

--
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
randy.yates@sonyericsson.com, 919-472-1124
 
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On 06 May 2005 11:40:59 -0400, Randy Yates
<randy.yates@sonyericsson.com> wrote:

>Loren Amelang <loren@pacific.net> writes:
>> [...]
>> I'm probably on the most lightly loaded cell in the system, in a
>> remote area no other company even bothers to serve, so it isn't a
>> matter of oversubscribing the hardware.
> ...
>Regarding your situation, perhaps you're at the distance limits of the
>cell, or the cell is operating at reduced power, thus they may be
>dropping to a lower speech codec rate in order to perform more channel
>coding.

I can see the tower, I get "five bars", and I'd be surprised if there
is anyone else using this particular cell at any given moment. I guess
they truly have optimized away any hope of bearable music performance.

>Have you tried a GSM phone? Most of the GSM networks now support AMR
>(Adaptive Multi-Rate), an improved variable-rate codec system.

As I said, there is literally no alternative here. Any other company
goes to "no service" about ten miles back toward civilization.

Loren
 
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On 6 May 2005 10:49:03 -0700, "KGT" <kgtracy@gmail.com> wrote:

>Randy
>To put this back on track.. what model GSM phone do you use as a
>benchmark of Good downlink SPEECH quality? Do you have one that you
>rate poor?
>
>Loren
>No currently deployed CELP coder (I believe AMR Is CELP?) can reproduce
>music well. Its meant for speech! No matter what the RF FER is.
>
>All
>I'm still interested in RAP opinions on phones that have surprized you
>with very good or very bad SPEECH.
>
>Thanks
>Kevin Tracy

Kevin,
Pardon me for persisting here, but my mention of unbearable music
performance is not a trivial aside - it is a serious complaint about
the performance of my phone. I understand you are charged with
optimizing speech performance, but since you are questioning the
existing performance standards, why not question that goal of "speech
only" as well?

My "audiophile ears" can tolerate FM radio multipath, AM radio skip
fading, and even just plain cheap distorted sound. But there is
something about the distortion of music and background sound through
the new phone that borders on pain - and I don't seem to be learning
to accommodate to it. Can I be the only one who notices this?

Try an experiment. Use your cellphone as your only phone for awhile,
not just for quick speech messages. Start noticing how often you get
stuck with music on hold, or talking to someone who is listening to
music or watching television. Ignoring music performance will limit
acceptance of cellular as an alternative to wired phones.

Loren
 
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Loren

Wow where should I start. In my 8 years of cellular Voice quality You
may just be the first person who have verbalized that you
A) care alot about music over cells
B) dont realize why this is not practical/possible given current
network capacity/bandwidth demands.

This is not a bandwidth limited analog network where both voice and
music are similarly degraded. This is digital with VOICE codecs that
have been squeezed to there last ounce of
compression. These are codecs not A to D / D to A converters. There
only tools are to save your speech as mathematic functions that
synthesize the basic mouth resonant filters /tone generation. This is
why music sounds bad because the resynthesis is working with functions
that are limited to specific mouth/ speech recreation.

As to this slowing the sucess and universal use of wireless/ devices..
do a google on market penetration. I'm more worried about keeping up!

Hope this helps
Kevin Tracy
 
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"KGT" <kgtracy@gmail.com> writes:

> Randy
>
> To put this back on track.. what model GSM phone do you use as a
> benchmark of Good downlink SPEECH quality?

Our Z500 sounds pretty sweet.

http://www.sonyericsson.com/z500a/

--
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
randy.yates@sonyericsson.com, 919-472-1124
 
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Randy Yates wrote:
> Loren Amelang <loren@pacific.net> writes:
>> [...]
>> I'm probably on the most lightly loaded cell in the system, in a
>> remote area no other company even bothers to serve, so it isn't a
>> matter of oversubscribing the hardware.
>
> Rappaport [1] states that QCELP13 is a higher-datarate speech codec
> for IS-95 systems. You can also read some interesting history about
> the CDMA codec evolution at
>
>
http://www.commsdesign.com/design_corner/showArticle.jhtml?articleID=16500249
>
> Regarding your situation, perhaps you're at the distance limits of the
> cell, or the cell is operating at reduced power, thus they may be
> dropping to a lower speech codec rate in order to perform more channel
> coding.
>
> Have you tried a GSM phone? Most of the GSM networks now support AMR
> (Adaptive Multi-Rate), an improved variable-rate codec system.
>
When I got my GSM phone almost a year ago, my connectivity dropped to about
half what it is now (Nashville--Cingular). My trusty old Nokia 51xx used to
connect reliably in my home. My new Sony-Ericsson: much less so. It
matters not if I have 'bars' or not. The night I got it, I experienced an
inability to connect, as did my wife, with the same model.

I booted up the Nokia and got a connection in the same place (no actual
'service' of course, only a recording).

jak

> --Randy
>
> [1] @BOOK{rappaport,
> title = "{Wireless Communications: Principles and Practice}",
> author = "{Theodore~S.~Rappaport}",
> publisher = "Prentice Hall PTR",
> edition = "second",
> year = "2002"}
 
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jakdedert wrote:
> Randy Yates wrote:
>> Loren Amelang <loren@pacific.net> writes:
>>> [...]
>>> I'm probably on the most lightly loaded cell in the system, in a
>>> remote area no other company even bothers to serve, so it isn't a
>>> matter of oversubscribing the hardware.
>>
>> Rappaport [1] states that QCELP13 is a higher-datarate speech codec
>> for IS-95 systems. You can also read some interesting history about
>> the CDMA codec evolution at
>>
>>
>
http://www.commsdesign.com/design_corner/showArticle.jhtml?articleID=16500249
>>
>> Regarding your situation, perhaps you're at the distance limits of
>> the cell, or the cell is operating at reduced power, thus they may be
>> dropping to a lower speech codec rate in order to perform more
>> channel coding.
>>
>> Have you tried a GSM phone? Most of the GSM networks now support AMR
>> (Adaptive Multi-Rate), an improved variable-rate codec system.
>>
> When I got my GSM phone almost a year ago, my connectivity dropped to
> about half what it is now (Nashville--Cingular). My trusty old Nokia
> 51xx used to connect reliably in my home. My new Sony-Ericsson: much
> less so. It matters not if I have 'bars' or not. The night I got
> it, I experienced an inability to connect, as did my wife, with the
> same model.

Meant to say (above) 'about half what it was before...'
>
> I booted up the Nokia and got a connection in the same place (no
> actual 'service' of course, only a recording).
>
> jak
>
>> --Randy
>>
>> [1] @BOOK{rappaport,
>> title = "{Wireless Communications: Principles and Practice}",
>> author = "{Theodore~S.~Rappaport}",
>> publisher = "Prentice Hall PTR",
>> edition = "second",
>> year = "2002"}
 
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KGT <kgtracy@gmail.com> wrote:
>
>Wow where should I start. In my 8 years of cellular Voice quality You
>may just be the first person who have verbalized that you
>A) care alot about music over cells
>B) dont realize why this is not practical/possible given current
>network capacity/bandwidth demands.

I can sort of understand him. Now, personally, I refuse to use cellphones
because the sound quality just drives me up the wall... I have a real hard
time telling what people are saying, and I can hear HF SSB stuff just fine.
Maybe it's the lack of sidetone that irritates me.

But I spend much of my day listening to music on hold, and I could see
that being a bad thing on a cellphone.

My wife often calls me on her cellphone from musical events, and the music
behind her turns into weird squealing and beeping on the phone, which
makes it that much more difficult to understand her voice... I think if
the music were not so weirdly altered that it would be less irritating.

But then, I have a WECO 500 set on my desk right now, which probably says
something about my attitude toward telephony. The 1A2 system is waiting
to get installed still.
--scott
>


--
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kludge@panix.com (Scott Dorsey) wrote in
news:d5gs5f$nd3$1@panix2.panix.com:

> But then, I have a WECO 500 set on my desk right now, which probably
> says something about my attitude toward telephony. The 1A2 system is
> waiting to get installed still.

And assuming the phone company still supports pulse dialing in 50 years, it
will still work and sound better than current digital phones.
 
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Carey Carlan wrote:
> kludge@panix.com (Scott Dorsey) wrote in
> news:d5gs5f$nd3$1@panix2.panix.com:
>
>
>>But then, I have a WECO 500 set on my desk right now, which probably
>>says something about my attitude toward telephony. The 1A2 system is
>>waiting to get installed still.
>
>
> And assuming the phone company still supports pulse dialing in 50 years, it
> will still work and sound better than current digital phones.


I certainly hope they do. I've got a nearly mint AE 50 that I'm going
to hang on the wall at the hotel.
 
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"jakdedert" <jdedert@bellsouth.net> writes:

> Randy Yates wrote:
>> Loren Amelang <loren@pacific.net> writes:
>>> [...]
>>> I'm probably on the most lightly loaded cell in the system, in a
>>> remote area no other company even bothers to serve, so it isn't a
>>> matter of oversubscribing the hardware.
>>
>> Rappaport [1] states that QCELP13 is a higher-datarate speech codec
>> for IS-95 systems. You can also read some interesting history about
>> the CDMA codec evolution at
>>
>>
> http://www.commsdesign.com/design_corner/showArticle.jhtml?articleID=16500249
>>
>> Regarding your situation, perhaps you're at the distance limits of the
>> cell, or the cell is operating at reduced power, thus they may be
>> dropping to a lower speech codec rate in order to perform more channel
>> coding.
>>
>> Have you tried a GSM phone? Most of the GSM networks now support AMR
>> (Adaptive Multi-Rate), an improved variable-rate codec system.
>>
> When I got my GSM phone almost a year ago, my connectivity dropped to about
> half what it is now (Nashville--Cingular). My trusty old Nokia 51xx used to
> connect reliably in my home. My new Sony-Ericsson: much less so. It
> matters not if I have 'bars' or not. The night I got it, I experienced an
> inability to connect, as did my wife, with the same model.
>
> I booted up the Nokia and got a connection in the same place (no actual
> 'service' of course, only a recording).
>
> jak

jak,

Which model Sony Ericsson are you using?
--
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%% Fuquay-Varina, NC % the Beatles on 'Hey Jude'"
%%% 919-577-9882 %
%%%% <yates@ieee.org> % 'Shangri-La', *A New World Record*, ELO
http://home.earthlink.net/~yatescr
 
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My Motorola V60 sounds better than any of the Ericsons I've had. I'm on
AT&T/Cingular service.

I have no idea what the oher stuff you asked about is as I use it as a
phone and require nothing else from it.

Eric
 
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On 6 May 2005 13:35:57 -0700, "KGT" <kgtracy@gmail.com> wrote:

>Loren
>
>Wow where should I start. In my 8 years of cellular Voice quality You
>may just be the first person who have verbalized that you
>A) care alot about music over cells
>B) dont realize why this is not practical/possible given current
>network capacity/bandwidth demands.

Kevin,

I'm familiar enough with coding to understand the choices the industry
has made, and the reasons for them. But those reasons are evaporating,
and I'm questioning the current direction of industry priorities. As I
said, even here in "Northwest Nowhere", I can use a 64K data pipe via
this same phone. If you believe the portable music hype, that is
capable of CD quality stereo music. In the city the cellular carriers
are heavily advertising their new full-motion video servies.

If there is now enough cellular bandwidth available for people to
watch video on demand, why can't we redirect a little bit of it toward
making the inevitable music during a voice call somewhat less toxic? I
bet if you gave your customers a "voice quality" option, they would
choose that long before the ability to watch an itty-bitty TV picture.

Loren
 
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